You're on the right track, acceleratedRendering must be in effect and the layermode must be "scrolling". However, only the topmost control is affected. Since your fields are in a group they are not candidates, the group itself is. The solution is to either ungroup the fields and scroll each one individually (if the text is longer than the field height) or scroll the entire group as a unit.

Edit : I guess the whole group is what you're doing already. When do you set acceleratedRendering? OpenStack? Preopencard?

With some complicated groups I do see some lag but others sometimes work smoothly. I haven't figured out what causes some scrollers to do that. Just in case, make sure none of the inside controls have a layermode set, they should all be static.

I just happened to think, are there subgroups inside the main group? If so, I've found that can slow down scrolling. I usually keep all the content inside the group as independent controls without any subgroups.